Figure 2

24-hour Cosine Curve fit to Mean Cerebral Blood Flow Velocity (cm/sec). Time course of CBFV according to time of day. Shown is a double plot of the group (n = 11) mean levels (+/- SEM) of CBFV (blue diamonds) fit with a 24-hour cosine curve (purple squares). Time of day is shown on the abscissa. The ordinate shows CBFV values (cm/sec). The vertical line indicates where the data was double plotted. Also displayed in the upper right corner is the non-linear cosine curve fit for mean CBFV, R² = 0.67. The overall mean circadian phase position of the minimum was 12:02 pm.